I married an RAF MR team member in 1978 and for the following 3 years it was a case of training every weekend and he was away in the brecons in all weathers. There were many call outs and he'd be gone for hours, days even, mostly searching for lost or injured SAS trainees but sometimes civies. He wasn't paid any different rate for doing it, RAF personal are paid 23.59 hres a day 7 days a week apparently, so he told me, but his day job was as an airframe technician on vulcans, when he was on a rescue he was slightly more risking his own health and life, the only time he was given any recognistion was when the RSPCA gave him a humanitarian award for rescuing some sheep from a gully.
The civilian MR teams are volunteers, I can't imagine how their families feel when they know they are on a call out looking for holiday makers and ramblers, climbers who have got it wrong.